Bearing construction



' June 4,-1946. A IY, DODGE I 2,401,557

vOriginal Filed June l 1 4 Mgg y 4 Patented June 4, 1946 Adiel Y. Dodge, Rockford, Ill.

Original .application June 16,` 1943, Serial No. 491,007. Divided and this application February 4, 1944, Serial No. 521,010

1 p 'I'his invention relates to bearing constructions and more particularly to anti-friction bearings for rotatably connecting coaxial races;

I, One of the objects of the vinvention is to pro'- vide a bearing construction in which the bearing elements are self aligning.

Another object of the invention is to provide a bearing construction in which the bearing elements produce a minimum of end thrust and in which scufilng of the races by the bearing e1ements is eliminated.

Another object of the invention is to provide 4 claims. (o1. aos-212) a bearing construction in which relatively narrow rollers are supported and guided from their end surfaces and have a barrel shaped rolling surface so that they can beguided easily.

Still another object of the invention is to provide a bearing construction employing relatively narrow rollers which arecapable of absorbing straight radial loads or `combined radial n and thrust loads. f

A further object of the invention is to provide short axial length relative to its diameter and is preferably of a length about one-half of its diameter. I have found that any length greater than one-half the diameter does not increase the load carrying capacity of the roller which is optimum when` the roller length is approximately one-half or slightly less than one-half its diameter. The end surfaces of the roller as shown at I5 are substantially flat' and parallel to form supporting and guiding surfaces and its side surface as shown at I6 is slightly barrelled. The radius of the side surface I6 in a plan'e passing through the roller axis is preferably at least four times and not more than six times greater than its radius in a plane transverse to the axis so that the roller will act in effect very much like a ball of large diameter insofar as its` bearing surface a bearing roller having its side surfaces curved in an axial plane about a radius different `than its radius of curvature in a plane transverse to the axis. i l

A still further object of the invention is to provide a bearing roller having a substantially pure rolling action with alminimum ofscrubbing or scufiing and which is therefore well adapted for high speed service. I

The above and other objects and advantages will be more readily apparent from the following description when readlin connection with the accompanying drawing, in which; ,l

Figure 1 is an axial sectionwith parts in ele on the races is concerned, while occupying only a fraction of the space required by such a ball.

The rollers are supported in an annular cage I 'l shown as formed of sheet metal channel shaped in cross section with parallel sides I8 and a web portion I9 formed with openings of slightly smaller circumferentiallength than the diameter of the rollers so that the rollers are separated by spaced parts of the web connecting the side portions. The side portions I8 have a running ilt vation of a clutch and bearing unit in which the bearing construction vention; t l

Figure 2 is'a side elevation of a bearing roller; Figure 34 is an end elevation of a bearingA roller; Figure 4 is a partial enlarged section illustrating the mountingof` cage; and t Figures 5 and 6 are diagrams illustrating the construction of the bearing rollers. l

The unit illustrated in Figure 1 is adapted to connect an outer race I 0 having a cylindrical inner working surface II to an inner race" I2 having a complementary outer cylindrical surface I3. It will be understood that either race embodies the present inthe bearing rollers in `a may be arranged for free rotation in either direction as desired.

In order to connect the races for free rotation, a bearing .unit is mounted therebetween comprising a series of bearing rollers I 4 shaped as best seen in Figures 2 and 3. Each of the rollers is of A onone of the races, `shown as` the `inner race, and fit closely against the flat ends I5 of the rollers to support and guide the rollers. When not assembled between the races, the rollers are held in the cage by engagement with the ends of the openings in the web I9 against radial out-4 ward movement and are prevented from moving radially inward in the cage byiinwardly bent parts of the side portions I8 as shown at 2l to form inwardly extending projections engageable with the rollers to limit inward movement thereof. p

Since the bearing rollers running on cylindrical races are guided almost entirely by the sides of the cage engaging the flat roller ends, it is necessary that the clearance therebetween be such as to limit tilting of the rollers to an amount which will not cause excessive tightening or binding. It is also necessary that the cage be supported independently of the'rollers and for this purpose the cage flanges form a close running fit on the inner cylindrical race. I havefound that the maximum permissible clearance between the roller ends and the cage sides may be calculated as follows, referring to Figures 5 and 6: i

Let r=radius of roller at right angles to roller axis and in the plane of rotation. Let R=radius of roller at right angles to roller axis and in a plane to the plane of rotation.

'Let c=elearance between roller and races.

Let z=clearance at one side of roller between roller and cage.r

Let h=height of chord of arc formed by R through angle V21.

' Let q =any ang1e of tilt of roher.

9o? to -122= (rh) X sec Therefore must be less than Zr-i-c. a controls the extent of @tangent of 2z =j While [the maximum clearance 2z which 'will control the rollers properly is expressed by the above equation, I prefer to design the rollers and cage to provide a clearance 2z about half that expressed by the equation. Y

When the bearing unit is to absorb end thrust it is preferably constructed as shown at the right of Figure' 1. This unit is adapted to operate between a conical surface 22 on the outer race and grippers' supported in a cage 21 between the two bearing units. When the cages are rotating relative to each other in one direction the grippers will tilt to a position in which they dlsengage the race/surfaces and when the cages are rotating inthe opposite direction the grippers will engage the race surfaces and drivably connect the races.

While one embodiment of the invention has been shown and described in detail herein, it will be understood that this is illustrative only and is not intended as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

y'1. In a bearing construction, a pair of coaxial races having roller engaging surfaces generated by rotating straight lines about the axis of the i races, a series of barrel shapedl rollers between the races whose length is approximately vone-half of their rolling diameter and whose contour radius is approximately four times their` rolling radius and whose ends are substantially flat and parallel, and a cage having substantially flat, side members contactingthe major portion of the roller ends, the cage side members being so spaced as to provide a total clearance between them and the roller ends less` than an amount which will allow the rollers to tilt to an extent atwhich their diameter in the plane of rotation is equal.

,Y to their central diameter plus the total clearance between the rollers vand the races.

2. In a bearing construction, a pair of races having spaced cylindrical surfaces, a series of barrel shaped rollers between the races, each of the rollers having a length approximately half .y its diameter and a contour radius approximately a complementary surface 23 on the inner race.

between the races under end thrust. The bearingrollers are identical with those described above and have been given the same reference numerals but are supported in an annular cage having' conical parallel sides 24 connected bya web portion 25 at right angles to the sides. `With this cage construction, the bearing rollers will be held at an angleras shown so that they are capable of absorbing end thrust as well as straight radial load.

I have found that with bearing rollers of this lcharacter the action more nearly simulatesthat of aball than of a roller and that the rollers can easily be guided by a slight guide pressure. Since their contact with the races is confined to the central portion they can easily be guided by a light side pressure and will not tend to become tilted so that they seuil' the races. Thus a minimum of end thrust in the bearing operation is developed and narrow rollers occupying a minimum of space can be employed to carry relatively large bearing loads.

The clutch unit shown in Figure 1 is more parcularly described and claimed in my copending application, Serial No. 491,007 flled June 16, 1943, of which this application is a division. As shown,

the `clutch unit includes a plurality of tiltable` four times its rolling radius and substantially flat :parallel ends, and a cage between the races haying flat side members for engaging the roller ends to hold the rollers against tilting and to guide them for substantially free rolling engagement with the races.

3. In a bearing construction, apair of coaxial races having roller engaging surfaces generated by rotation of substantially straight lines about the axis of the races, a series of' rollers between ,the races Whose contour radius is greater than their rolling radius and which have substantially flat parallel ends, the rollers having substantially spot contact with the race surfaces whereby they roll freely on the race surfaces, and a cage having side rings( which are substantially straight circumferentially engageable with the flat ends of the rollers to guide the 'rollers circumferentially and to limit tilting thereof. e

4. In a bearing construction, a pair of coaxial races having roller engaging surfacesgenerated by rotation of substantially straight lines about the axis of the races, a series of rollers between the races whose contour radius is approximately four times their rolling radius and which have substantially flat parallel ends, the length of the rollers being less than their diameter whereby f their ends are relatively large compared to their lengths, the rollers having substantially spot contact with the race surfaces to roll freely on the race surfaces, and a cage having side rings formed with substantially fiat surfacesw engageable with the roller ends to guide the rollers and to limit tilting thereof.

i ADIEL Y. DODGE, 

